Telephone-exchange system



c. w. KECKLER.

TELEPHONE EXCHANGE SYSTEM; APPLICATION FILED OCT- 30. 1917- Patented June 13, 1922.

l J li hts .1 Mild ensures up neckline, or NEWARK, New JERSEY, assrenon To urnsrnn-nniincrnio COMPANY, INCORPORATED, on NEW YORK, N. Y, A oonroiaia'rron on NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Fatent. Patented Jung 13,

Application filed October 30, 1917. Serial No. 199,235.

To aZZ whom it may concern Be it known that 1, CHARLES 1V. KEGKLER, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Telephone-EX- change Systems, ol which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and more particularly to such systems of the central energy type.

The object of this invention is to provide improved signaling means for systems of this character.

In accordance with this invention there is provided a trunk circuit extending between operators positions which is equipped w th apparatus by means of which, when the incoming end thereof is connected with a telephone line to which a cord circuit or another trunl: circuit is connected, the supervisory signaling device in cord circuit connected with the other end thereof is caused to operate intermittently to indicate to the operator that the trunk circuit has been connected with a busy line. Upon the disconnection of the cord or trunk circuit which has rendered the line busy, apparatus in the secondtrunk circuit is renderedeffective to cause the continuous operation of the supervisory signaling device to indicate to the operator that the called-tor line may be now signaled.

For a more complete understanding of this invention reference is to be had to the following description considered in connection with the accompanying drawing illustrating one embodiment of this invention.

There are shown in the drawing two telephone lines A and B, which terminate at difi crcnt operators positions. The line circuit A may he conncctcd'with a cord circuit C in any desired manner. The cord circuit C and the line B may he joined together by means of a trunk circuit D. The apparatus shown to the left of the dotted line 2--2 is at the originating operators position X and that to'thc right oil this line is at the terminating or trunk operators position Y. It is to be understood that a plurality of lines similar to A and a plurality of cord andtrunk circuits similar to C and D may he provided, but for the sake of convenience, only the two lines and one cord and one trunk circuit are shown in the drawing.

Assuming that after ubscriber A. 1s connected with the cord circuit the operator learns that connection is desired with the line of subscriber B, the operator at position X communicates with the operator at position Y over an order wire circuit (not shown), whereupon the distant or trunk op erator will assign the trunk circuit to be used. t will be assumed that trunk circuit D has been assigned. The originating operator thereupon inserts plug 5 into jack 6, whereupon relay '7 of the trunk circuit and relay 8 of the cord circuit C are operated over a circuit from battery through the lower winding of relay 7 lower normal contact of relay 9, tip contacts of the jack 6 and plug 5, winding of relay 8, ring contacts of the plug 5 and ack 6, upper normal contact of relay 9' and upper winding of relay 7 to ground. Relay 7, in operating, causes lamp 10, associated with the incoming end of the trunk circuit D, to be lighted over a circuit from battery through the lamp 10, lower normal contact of relay 11 and alternate contact of relay 7 to ground. The operation of relay 8 causes supervisory lamp 12 to be lighted; If the line B is busy when the incoming end of the trunk eircuit D is connectcd therewith, the lamp 12 will be caused to glow intermittently; while, if the line is not busy when connection is made therewith, the lamp 12 will. glow continuously to serve as a. ringing signal. The trunk operator upon obsorviu the lighted condition of lamp 10, indicating that connection has been made with the assigned trunk circuit, immediately inserts plug 15 thereof in jack 16 of line B. Relay 1? is thereupon operated in series with cut-off relay 18. Re lay 1.7 in operating causes the operation of relay 11, thereby opening the circuit oi? lamp 10, extinguishing the lamp. If, when plug 15 is inserted in the jack 16, a cord circuit or another circuit similar to'D is connected with jack 19 of line B, battery is then connected through the ring strand of the previously connected cord or trunk circuit to the ring contact of jack 19, so that upon the in sertion of the plug 15 into'jack 16 relay 20 operates. The operating circuit for this relay 20 is from battery in the cordor trunk circuit connected with jack 19, over the ring strand and contact thereofl'ring contacts of jack 16 andplug 15, right-hand normal con tact of relay 21 and the right-hand winding of relay 20 to ground. Relay 20, in operating, opens its normal and closes its alternate contacts. The closure of the right-hand alternate contact causes the operation of relay 22 over a circuit from battery through the contactof relay 17, right-hand alternate contact of relay 20, and the winding of relay 22 to ground. Relay 22 in operating completes a locking circuit for itself through its lefthand contact and prepares at its right-hand contact a circuit for relay 21. The closure of the left-hand alternate contact of relay 20 connects an interrupter 23 in circuit with the upper winding of relay 9, thereby causing the intermittent operation of this relay 9. In the intermittent operation of relay 9, contacts in circuit with supervisory relay 8 of cord circuit C are alternately opened and closed, thereby causing the alternate de energization and energization of relay 8, which results in the intermittent lighting of the supervisory lamp 12. This intermittent glowing of lamp 12 serves as the signal to the originating operator that the incom ing end of the trunk circuit D has been con nected with a busy line. Relay 9, in opening its normal contacts which are in circuit with the windings of relay 7, does not JGIlllii? this relay 7 to be released, for the closure of the alternate contact of relay 9 establishes a holding circuit through the lower winding of relay 7, thereby maintaining it energized. As long as the plug 15 remains connected with the jack 16, whileanother cord or trunk circuit is connected with another jack thereof, the supervisory lamp 12 will be lighted intermittently. The calling subscriber may thereupon be advised. that the wanted line is busy, and, if the calling party so desires, the connection may remain set up as a waiting connection until the cord or trunk circuit rendering the line B busy is disconnected, when the lamp 12 will glow continuously to serve as a ringing signal to the originating operator. It will also be observed that even it the originating operator should actuate the ringing key 30 while the trunk circuit is connected with a busy line, the source of ringing current 85 cannot be connected therewith, for the ring strand is open at the alternate contact of relay 2!.

\Vhen the trunk or cord circuit which has rendered line Bbusy is disconnected from the jack o'l line B, the circuit through the righthaud winding of relay 20 is opened at the jack contact. \Vhen relay 11 was operated asbetore described a circuit was completed vfrom battery through interrupter 25, lethand normal contact of relay 21, left-hand winding of relay 29, and the middle alternate contact of relay 11 to ground. An intermittent energizing circuit was thereupon completed for relay 29. If this energizing circuit including the interrupter 25 is closed at the time the circuit through the righthand winding of relay 20 is interrupted,

relay 20 will be maintained energized until interrupter 25 reaches an insulating segment, thereby opening the circuit through the letthand winding of relay 20. Relay 20 thereupon immediately releases its armatures, disconnecting interrupter 23 from circuit rela tion with relay 9 and stopping the intermittent lighting of the supervisory lamp 12. Relay 8 of the cord circuit C will remain energized, causing the lamp 12 to glow continuously to indicate a ringing signal to the originating operator. The closure of the right-hand normal contact of: relay 20 causes the operation of relay 21 over a circuit from battery through the contact of relay 17, normal contact of relay 20, winding of relay 21 and the right-hand contact of relay 22 to ground. Relay 21, in operating, introduces a break in the circuit including the interrupter 25 and the left-hand winding of relay 20, and by the opening of its right,

hand normal contact introduces another break in the circuit including the right-hand winding of relay 20. The closure of the alternate contact of relay 21 closes the normally open ring strand of the trunk circuit D. The originating operator noting the change in the character of the signal given by the supervisory lamp 12, knows that she may now signal subscriber This is done by actuating ringing key 30, whereupon relay 32 ol? the trunk circuit is operated by current from the source of ringing current Relay 32 in operating causes the operation of a ringing relay 3&- over a circuit from battery through the contact of relay 32, winding or". relay 3 1, and lower winding of relay 9 to ground. Relay 8&- in operating connects the source of ringing current 35 with the line B to cause the operation of the usual call bell at station 13. During the time that the ringing key 30 is operated, relay 9 is energized, thereby causing the deenergization ot supervisory relay 8 so that the lamp 12 will be extinguished while the operator is signaling the wanted line. The ringing key 30 upon being restored to normal position causes the release of relays 9 and 34: and the operation of relay 8, thereby relighting the supervisory lamp 12. The called subscriber l% in responding to the operation of the call hell removes the receiver from the switchbook, thereby causing the operation of the supervisory relay 36. In operating relay 36 causes the energization of relay 9 over a circuit "from battery through the contact of supervisory relay 86, left-hand normal contact of relay 20, the upper winding of relay 9 and alternate contact of relay to ground. Relay 9 in operating causes the release of relay 8, thereby extinguishing the supervisory lamp 12, whichindicates to the originating operator that the called party has answered.

.At the conclusion of the conversation the subscribers restore the receivers to the switchhooks. The restoration of the receiver the plug 5 from the ack 6, whereupon relay 7 releases its armature, completing a circuit for, and causing the lighting of, the lamp 10.,

This circuit may be traced from battery through the lamp 10, lower alternate contact of relay 11, and the normal contact of relay 7 to ground. The trunk operator observing the lighted condition of lamp 10, which serves as a disconnect signal, may withdraw the plug 15 from the jack 16, whereupon all apparatus is restored to normal condition.

If when the plug 15 1S inserted in the ack '16 no other cord or trunk circuit is connected with another ack of line B, no circuit willbe completed through the right-hand winds ing of relay 20, but when the conducting seg ment of interrupter 25 bridges the brushes thereof, a circuit is completed through the left-hand winding of relay 20, so that it attracts its armatures, causing the energization and locking up of relay 22. The length of time that the brushes of interrupter 25 are bridged by the conducting segment thereof is not suilicicnt to cause the intermittent lighting of the supervisory lamp 12. Upon the subsequent engagement of the insulating segments of interrupter 25 with the brushes thereof, relay 20 is released as hereinbefore described, thereby completing the circuit of relay 21.. From this point on, the operation is as before described.

From the above description it will be apparent that by utilizing theapplicants invention in telephone systems a positive signaling means is provided, by means of which the originating operator may be advised of the progress in setting up connections between subscribers. By utilizing applicants invention a very simple signaling scheme is provided for use in telephone systems where it is desirable to establish waiting connections.

lVhat is claimed is:

1. A telephone exchange system comprising a telephone line terminating at a switchboard section, a plurality of trunk circuits extending therefrom to a second section, one of said trunk circuits being connected to the telephone line, a link circuit'at the secend section connected with another of the trunk circuits, a signaling device in the link circuit, a relay operated irrespective of the operation of any other apparatus in the trunk circuit of which said relay forms a part due to the connection of a second trunk circuit with the tele shone line to cause the signaling device to furnish an intermittent signal, and means responsive to the disconnection of the first trunk circuit from the line to cause the signaling device to furnish a continuous signal.

2. A telephone exchange system comprising a telephone line, a link circuit connected with the line, a second link circuit comprising a normally open talking strand, a signaling device, and a relay normally connected with the talking strand and initially energized thereover upon connection of the second link circuit with the telephone line, interrupter mechanism brought into operative relation'with the signaling device by the operation of the relay to cause the intermittent operation thereof, circuit connections rendered'elfective upon the disconnection of the first link circuit from the line for causing the continuous operation of the signaling device, anda relay also responsive to the from the line for disconnectingthe first mentioned relay from the talking strand and closing the talking strand.

3. A telephone exchange system comprising a telephone line terminating at a switchboard" section, a plurality of trunk circuits extending therefrom to-a second section, one of" the trunk circuits being connected with the telephone line, talking conductors therefor; a link circuit at the second section connected'with another of the trunk circuits. a signaling device in the link circuit, interrupter mechanism, an electromagnetic switching device energized over a path in cluding a portion of the talking conductor and irrespective of the operation of any other apparatus in the trunk circuit of which said switching device forms a part due to the connection of the second trunk circuit with the telephoneline to operatively associate the signal device and interrupter mechanism whereby the signaling device is intermittently operated; and circuit connec tions renderedeffective-upon the disconnection of the first trunk circuit from the line to cause the continuous operation of the signal device,

4. A telephone exchange system comprising a telephone line terminating at a. switchboard section, a plurality of trunk circuits extending therefrom to a second section, one of the trunk circuits being connected to atelephone line, talking conductors therefor, alink circuit at the second. section connected with another of the trunk circuits, a relay in thelink circuit bridged across the talk ing circuit thereof, a signaling device at the second-section controlled by the link circuit relay, a rclay in the second trunk circuit energized over a path includingaportion of the talking conductor and irrespective of the operation of any other apparatus in the trunk circuit of which said relay forms a part due to the connection thereof disconnection of the first link circuit with the telephone line, and an interrupter operatively associated with the talking cir cuit of the connected link and trunk circuits by the operation of the trunk relay to cause the intermittent energization of the link circuit relay whereby the signaling device is intermittently operated, aid trunk relay being deencrgized upon the disconnection of the first trunk circuit from the telephone line to discontinue the operative association of the interrupter and said talking circuit whereby the signaling device is continuously operated.

5. A telephone exchange system, comprising a telephone line tern'linating at a switchboard section, a plurality of trunk circuits extending tl'ierefrom to a second section, one of the trunk circuits being connected with the telephone line, talking conductors there-. for, a link circuit at the second section connected with another of the trunk circuits, two relays energized upon the connection of the second trunk circuit with the line, one over a local circuit, the other over a path including a. portion of the talking conductor and irrespective of the operation of any other apparatus in the trunk circuitof which said relay forms a part, a third relay oper ated upon the energization of the two relays and thereafter rendered independent of the talking circuit relay, and a fourth relay energized upon the deenergization ot the talk ing circuit relay to disconnect the talking circuit relay from the talking conductor.

6; A telephone exchange system comprising a telephone line terminating at a switchboard section, a plurality of trunk circuits extending therefrom to a second section, one of said trunk circuits being telephonically connected with the telephone line, a link circuit at the second section connected wit-h another of the trunk circuits, a signaling device in the link circuit, a relay operated irrespective of the operation of any other appa- "ratus due to the connection of the second trunk circuit with the telephone line to cause the signaling device to furnish an in termittent signal, and means responsive to the disconnection of the first trunk circuit from the line to cause the signaling device to furnish a continuous signal.

7 A telephone exchange system comprising telephone line terminating at a switchboard section, a plurality of trunk circuits extending therefrom to second section, one of the trunk circuits being telephonically connected with the telephone line, talking conductors therefor, a link circuit at the second section connected with another of the trunk circuits, a signaling device in the link circuit, interrupter mechanism, an electromagnetic switching device energized over apath including a portion of the talking conductor and irrespective of the operation of any other apparatus due to the connection of the second trunk circuit with the telephone line to operatively associate the signal device and interrupter mechanism whereby the signaling device is intermittently operated, and circuit connections rendered effective upon the disconnection of the first trunk circuit from the line to cause the continuous operation of the signaling device.

8. A telephone exchange system comprising a. telephone line terminating at a switchboard section, a plurality of trunk circuits extending therefrom to a second section, one of the trunk circuits being telephonically connected to a telephone line, talking conductors therefor, a link circuit at thesecond section, connected with another of the trunk circuits, a relay in the link circuit bridged across the talking circuit thereof, a signaling device at the second section controlled by the link circuit relay, a relay in the second trunk circuit energized over a path including a portion of the talking conductor and irrespective of the operation of any other apparatus due to the connectionthereof with the telephone line, and an interrupter operatively associated with the talking circuit of the connected link and trunk circuits by the operation of the trunk relay to cause the intermittent energization of the link circuit relay whereby the signaling de vice isintermittcntly operated, said trunk relay being deenergized upon the disconnection of the first trunk circuit from the telephone line to discontinue the operative association of the interrupter and said talking circuit whereby the signaling device is con tinuously operated.

9. A telephone exchange system, comprising a telephone line terminating at a switchboard section, a plurality of trunk circuits extending therefrom to a second section, one of the trunk circuits being telephonically connected with the telephone line, talking conductors therefor, a link circuit at the second section connected with another of the trunk circuits, two relays energized upon the connect-ion of the second trunk circuit with the line, one over a local circuit, the other over a path including a portion of the talking conductor and irrespective of the operation of any other apparatus, a third relay operated upon the energization of the two relays and thereafter rendered independent of the talking circuit relay, and a fourth relay energized upon the deenergization of the talking circuit relay to disconnect the talking circuit relay from the talking conductor.

In witness whereof, I hereunto subscribe my name this 26th day of October A. D.,

CHARLES W. KECKLER. 

